David J. Spencer

Knitting Technology : A Comprehensive Handbook and Practical Guide, Third Edition

Knitting & Crochet, Needlework, Organization, Storage & Trans Daviss Comprehensive Handbook of Laboratory and Diagnostic Tests With Health Informatics: Practical Guide for Healthcare and Information Technology Biomaterials Science, Third Edition: An Introduction to Materials in Medicine. A Practical Guide to SysML, Third Edition, fully updated for SysML version 1.4, provides a comprehensive and practical guide for modeling systems with SysML. With their unique perspective INCOSE Systems Engineering Handbook: A Guide for System Life Cycle Processes and Activities. INCOSE Knitting · Goodreads Knitting is a method by which yarn is manipulated to create a textile or fabric. A third method, called combination knitting, goes through the front of a knit stitch and the back of a purl stitch. The Columbia Electronic Encyclopedia, Sixth Edition. Knitting Technology: a Comprehensive Handbook and Practical Guide.

An Introduction to Textile Technology

The word “textile” originates from the Latin verb “ texere ,” which means “to weave;” however, as the textile institutes terms and definitions glossary explains, it is “a general term applied to any manufacture from fibers, filaments, or yarns that are characterized by flexibility, fineness, and high ratio of length to thickness.” Textile fabrics can be produced from webs of fibers by bonding, fusing, or interlocking to make non-woven fabrics and felts; however, their physical properties tend to restrict their potential end-usage. The mechanical manipulation of yarn into fabric is the most versatile method of manufacturing textile fabrics for a wide range of end-uses. The methods of mechanically manipulating yarn into textile fabrics include: interweaving, intertwining, and interlooping. These methods have evolved from hand-manipulated techniques through their application on primitive frames into sophisticated manufacturing operations on automated machinery. Knitting is the most common method of interlooping and is second only to weaving as a method of manufacturing textile structures. Although the capability of knitting to manufacture shaped and form-fitting articles has been utilized for centuries, modern technology has enabled knitted constructions in shaped and unshaped fabric form to expand into a wide range of apparel, domestic, and industrial end-uses.

Aspects of Knitting Science

Weft knitted structures—especially those used for hosiery, knitwear, and underwear—have unique properties of form-fitting and elastic recovery based on the ability of knitted loops to change shape when subjected to tension. Dimensional changes can occur during production or washing and wearing when problems of shrinkage and size variation can cause customer dissatisfaction and increase production costs. Changes of dimension after knitting can create major problems in garments and fabrics especially those produced from hydrophilic fibers, such as wool and cotton. Articles knitted from synthetic thermoplastic fibers, such as nylon and polyester, can be heat set to a shape or dimensions that are retained unless the setting conditions are exceeded during washing and wear. In the case of wool fibres, this effect can be magnified by felting shrinkage. When untreated wool fibres are subjected to mechanical action in the presence of moisture, the elasticity and unidirectional scale structure of the fibres causes them to migrate and interlock into a closer entanglement. On circular knitting machines, higher productivity involves faster needle movements as a result of an increase of knitting feeds and machine rotational speed.

25 – Plain tricot structures knitted with two full set guide bars

Plain tricot structures knitted with two full set guide bars are the most popular of all warp knitted structures and are based on a two-course repeat cycle with a change of direction lap at each course. Although the majority has been made on 28-gauge tricot machines using 40 denier Nylon, other gauges, yarn types, and counts, as well as Raschel machines, are used. The two bars make different lapping movements because otherwise, a structure having single needle bar characteristics would be produced. Each guide bar contributes a thread to every overlap, and the two underlaps are distinguished as they lap to a different angle, extent or direction. Under normal conditions, the threads of the front guide bar tend to dominate the face as well as the back of the fabric. Two bar tricot is the simplest two-bar structure and uses a minimum amount of yarn.

8 – The various types of weft knitting machines

This chapter provides an account of the different types of knitting machines. Weft knitting machines are grouped as fabric machines—knitting fabric in a continuous uninterrupted length of constant width—or garment length machines—which have an additional garment-control mechanism to coordinate the knitting action in the production of a garment length, structured repeat sequence in a wale direction. Fabric, yard-goods or piece-goods machines knit fabric at high speed, which is manually cut away from the machine, usually in roll form, when a convenient length has been knitted. Most fabric is knitted on circular machines of the revolving needle cylinder type because of their productivity; it requires splitting into open width unless used in tubular body width. It is finished on continuous finishing equipment and is cut and sewn into garments or it is used for household and industrial fabrics. The productivity, versatility, and patterning facilities of fabric machines vary considerably. Garment length machines tend to be in coarser gauges than the fabric machines.

19 – Automatic power flat knitting

The difference between the simple hand flat and the automatic power flat is that the latter can be programmed to knit through a garment length sequence at high speed and has greater patterning facilities. This chapter illustrates the arrangement of elements in the needle bed of a machine having full mechanical selection. A separately controlled arrangement is available on the other bed. In the tricks beneath each needle are selectors whose tails are supported by a jacquard steel, which extends across the full width of the needle bed. The steels are hinged together to form an endless “chain loop,” which passes over the prism. While the cam-carriage is clear of the needle bed at the end of its traverse, the prism can turn, bringing steel onto its upper surface and thrusting it upwards into contact with the protruding tails of the selectors producing a simultaneous selection at every needle trick for the next carriage traverse. The prism can dwell to repeat a selection, or rack forwards or backwards by one or two positions. The pasteboard cards provide the unit with the data to control and coordinate the machines functions in the garment length knitting sequence.

11 – Pattern and selection devices

Simple patterning and quick rib changes can be achieved in a limited width repeat when element butts are at one of a range of lengths or positions that are associated with particular raising cam arrangements. The cam arrangement and element butt repeat set-out determines the pattern area. Popular methods employ different butt lengths and cam thicknesses or different butt positions and cam tracks. Some selection devices, including pattern wheels, operate onto element butts of one height position, many patterning arrangements involve the use of a single selection butt for each element placed at one of a choice of height positions. The total number of different heights directly influences the width repeat in Wales. It is convenient to arrange and retain a butt set-out, which is a factor of the needle bed so that the pattern widths exactly repeat across it. The two most common geometrical butt set-outs are straight and mirror repeat although combinations of the two are possible. Selection devices vary in their facilities and their pattern changing and pattern-area capabilities.

10 – Coloured stitch designs in weft knitting

Ornamentation for design purposes might be introduced at the fiber, the yarn, or the dyeing and finishing stage as well as at the knitting stage. Apart from different colors, it might take the form of structural or surface interest. In fiber form, it can include a variation of fiber diameter, length, cross-section, dye uptake, shrinkage, and elastic properties. The dyeing process, which provides the possibility of differential and cross-dyeing of fabrics with more than one fiber, might occur at any point in manufacturing from fiber to finished article. The finishing process transforms the appearance of a relatively uninteresting structure either as an allover effect or on a selective basis; it might also introduce heat or chemically derived shaping. Printing and particularly transfer printing introduce colored designs onto plain color surfaces while embroidery stitching produces relief designs motifs in one or more colors. The knitting of stitch designs involves a loss of productivity compared with the knitting of plain unpatterned structures.

28 – Multi guide bar machines and fabrics

Many factors have contributed to the success of warp knitting in the production of lace, curtain-net, and elastic fabrics. The chapter discusses that on conventional multi-guide bar machines, pattern guide bars are only required to supply one thread each for a pattern repeat width, and sometimes these are of different counts or types to achieve greater effect. To use ordinary guide bars for this purpose would be uneconomical as their weight would lower the machine speed. Only about 8 to 13 shogging or displacement positions are available so the patterning capabilities would be restricted. Instead, light-weight pattern guide bars are used, which have drilled holes to which finger guides are screw-attached only at the required spacing for the pattern. Up to four pattern bars can be “nested” together so that their guides converge into the same displacement line and they swing as a single guide bar, but they are shogged independently although guides of bars in the same nest cannot cross or approach within two needle spaces of each other. Elasticized fabrics have long been used for corsetry, foundation garments, and swimwear but the introduction of fine-diameter elastane yarns whose elastic extensibility and recovery can be “engineered” to particular requirements has extended the use of these structures into lingerie, and active sports and leisure wear.

23 – Basic warp knitting principles

In a warp knitted structure, all ends supplied from the same warp sheet have identical lapping movements because each is lapped by a guide attached to the same guide bar. Beams supply the warp sheets in parallel form to the guide bars whose pattern control determines the timing and configuration of the lapping movements in the form of overlaps and underlaps. The needles intermesh the new overlaps through the old overlaps to form the intermeshed loop structure. To ensure uniform conditions of warp feed and tension, the ends are supplied from flanged beams attached to shafts that turn to unwind the warp sheet in parallel formation. For convenience of handling, a number of beams are attached to a beam shaft to achieve the full width of warp sheet. Each guide bar is supplied with a warp sheet from its own beam shaft to suit its requirements of threading and rate of warp feed for its particular lapping movement. Warp guides are thin metal plates drilled with a hole in their lower end through which a warp end might be threaded if required, they are held together at their upper end in a metal lead and are spaced in it to the same gauge as the machine.